Method of making a ball head bearing



R. E. POIRIER 3,126,612 Memos OF MAKING A BALL HEAD BEARING Filed March3. 1961 /4 INVENTOR bearing surface.

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Patented Mar. 31, 1964 3,126,612 METHOD OF MAKING A BALL HEAD BEARINGRobert E. Poirier, Ferndale, Mich., assignor to Chrysler Corporation,Highland Park, Mich., a corporation of Delaware Filed Mar. 3, 1961, Ser.No. 93,118

Claims. (Cl. 29-1495) This invention relates to improvements in a methodof making a ball head bearing for use in a coupling in a vehicle wheelsuspension comprising a shaft having a ball head pivotally seated in agreaseless plastic socket.

In such a construction the outer surface of the ball head or end servesas a load sustained thrust bearing and must comprise a smooth sphericalbearing surface to prevent destruction of the comparatively soft plasticmaterial of the mating ball receiving socket. Heretofore such ball endshave beenformed oversize by various forging or casting methods, theliground to the desired spherical Such a procedure is costly and hasaccordingly not been considered to be commercially feasible in thehighly competitive and cost conscious automobile manufacturing industry.

An important object of the present invention is to provide an improvedball and socket type universal coupling and method of fabricating thesame'which are simple, efiicient, and economical, the coupling beingparticularly suitable for use in the thrust or compression type vehiclewheel suspension, or at the vehicle steering gear tie rod ends, by wayof example.

In the usual formation of a ball head shaft by conventional forgingmethods, a rough forging seam results at the outer end surface of theball head. This seam must be ground to'a smooth spherical finish beforethe ball head can be used efficiently as a thrust bearing. Also inaccordance with conventional forging practice, a reversely curvedportion of the shaft results where the base of the ball head joins theshaft stem. Such a formation limits the pivotal movement of the ballhead in its socket and must be ground away to obtain optimumeffectiveness of the coupling.

view of a rod to be forged into a ball head coupling in accordance withthe present invention.

FIGURE 3 is a fragmentary mid-sectional view of the rod of FIGURE 2,showing an early stage in the formation of the coupling.

FIGURE 4 is a view similar to FIGURE 3, showing a more advanced stageinthe formation of the coupling.

FIGURE 5 is a view similar'to FIGURES 3 and 4, showing the completedball head shaft.

FIGURE 6 is a view similar to FIGURES, showing the ball head confinedwithin a mating plastic socket member.

FIGURE 7 is a reduced view similar to FIGURE 6, showing the socketmember assembled within a retainer portion of the suspension.

It is to be understood that the invention is not limited in itsapplication to the details of construction and arrangement of partsillustrated in the accompanying drawings, since the invention is capableof other embodiments and of being practiced or carried out in variousways. Also it is to be understood that the phraseology or terminologyemployed herein is for scription and not of limitation.

Referring to the drawings, an embodiment of the present invention isillustrated by way of example in an the purpose of deautomobile wheelsuspension comprising upper and lower Other objects are accordingly toprovide an improved ball head shaft for use in a universal couplingwherein the ball head is readily and economically manufactured by coldforging operations that avoid the formation of a forging seam on thebearing surface of the ball head, as well as the formation of thereversely curved portion at the base of the ball head. Thus theoperations of removing such a seam and reversely curved portion areeliminated and economies are effected.

Still another object is to provide an improved ball head shaft andmethod of making the same wherein a portion of the shaft spaced from theball head is forged to an enlarged diameter, thereby to provide anenlarged body [for securing the shaft to a suitable support and toprovide a reduced diameter neck for the shaft adjacent the ball head. Ineffect an undercut ball head is provided on a shaft body without thenecessity of cutting away any portion of the shaft to form the reducedneck. In consequence, the reduced neck, which'is desired to enhance thepivotal adjustab-ility of the coupling, issimply and economicallyachieved.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingsforming a part of this swinging control arms 10 and 12 connected withthe upper and lower ends of a spindle support 14 by means of ball andsocket type universal couplings l6 and 18 respectively. The support 14carries a steering knuckle 20 on which a wheel is journalled in acustomary manner. The couplings 16 and 18 are similar, so that only oneis described in detail herein.

The upper coupling 16 for example comprises a cylindrical shaft 22having an integral coaxial enlarged conically tapered body 21 whichterminates in a threaded lower end 23. The body 2lis seated in a matingtapered socket in an upper bracket 24 of support 14 and is suitablysecured thereto by a nut 25 screwed on end 23 which projectsbelowbracket 24. An integral ne'ck 22a of shaft 22 extends coaxiallyupwardly from the enlarged body 21 and terminates in an integralenlarged spherical ball head 26 confined within a mating sphericalsocket 28 in a plastic bearing member 30. The latter in turn is confinedwithin a hollow retainer 32 comprising a downwardarm 10 to substantiallyclose the opening of retainer cup 32, FIGURE 7.

In the construction shown, the shaft 22 is under compression' and theball head 26 comprises a thrust hearing which sustains in part theweight of the automobile. The

control arms 10 and 12 are pivotally mountedon the vehicle chassis inaccordance with conventional practice, so that the mating sphericalbearing surfaces of the socket 28 and ball head 26 are in constantuniversal pivotal movement with respect to each other when subject toroad bounce and vehicle steering. The plastic member 30 preferablycomprises a smooth resilient bearing material such as nylon or Teflonwhich when suitably confined as in the retainer 32 affords an excellentgreaseless load sustaining bearing surface for the spherical ball head26. Because of the comparative softness of the plastic material ofbearing 30 with respect to the steel head 26 and the susceptibility ofthe plastic material to abrasion, the spherical surface of head 26 mustbe smooth and free from recesses into which the plastic bearing 30 couldbe extruded when subject to compressive force.

3 To the above end, the present invention provides an improved method offabricating an integral ball head shaft which achievesthe requisitesmoothness and also results in a coupling 16 capable of maximumuniversal v pivotal movement in a socket of the character described,

both without recourse to grinding and polishing operations ordinarilyrequired to complete such a structure. Referring to FIGURE 2', the shaft22 is formed from a suitable length of malleable cylindrical bar stockwhich is mushroomed at one end, FIGURE 3, to form a rounded andpreferably spherically crested dome 26b having a flared annular base260. Also by either conjoint or suc cessive operations, the rod or shaft22 is enlarged at 21 belowthe base 260 to provide the coaxial downwardlyconverging conical body 21, the portion of the shaft 22 below the body21, as well asuthe neck portion 22!: be-

tween theenlargements;-2lta-nd1266remainingundeformed at the initial'diameleb'tdf fheirod-ZZ of FIGURE 2. The lower end ofrotl or'shaft22is'thus' available for threading at 23 in acbor'tlarice withcbnvenli'orra'l pt actiic .fil l v Preferably in formingthe enlarg'enib'fit ZI J th shaff. 22 is gripped above and below t 'hertigidh"tfi be nl'arged and is cold forged to the 'desirdshhple-bycompressional force and suitable die means ti bll -knowhfitothe art; Similarly'rin forming tf illf niii.sli ikioi'netl end}; the -ffl- 2 pp in 'a idie adjacenethe-96am te lie musur whereupon 't 26f:-coaxial with slia ftl' s illii'strated,

from at'38. Simultaneously the spherical shape of the dome 26b isextended to approximately a semi-sphere merging tangentially with thecylindrical sleeve or base I 26d. The sleeve 26d is then engaged frombelow and laterally and cold forged to the completed spherical shapecoaxial ,with shaft 22, FIGURE 5, whereby the space 38 is reduced andmay be completely enclosed.

By virtue of the construction described, the final forging seam 40comprises an annular rounded lower edge of base'26d adjacent the shaft22b and is thus located where i il eri'd -is""co'ld sergea ts itiiesynlm'eftrien spinning or rollingoperations.

it does not come into thrust bearing contact with the inner plasticbearing surface of the socket 28. Also as a consequence'of forming thebase 260 and then deforming it successively to the cylindrical andspherical configurations 26d, FIGURES 4 and 5, a rounded annular edgefor the forging seam 40 is readily obtained as an inherent result of theforging operations. The rounded lower edge at the forging seam 40 avoidsa reversely curved juncture between the final spherical surface of theball head 26 and the neck- 22:: of shaft 22. Such a juncture comparableto the radius 42 at the juncture between the initially formed mushroombase 260, FIGURE 3, and rod 22 is,. om mo nly formed by other processesand must be rehaywi e epa'ra'te operation in orderto obtain maxi-- mumstippcittingigcdntact, between the under portions of I head '26 Thespherical bal ahead; rolled by conventional means to spherical bearingsurface required and is then forced into socket 28 through the lattersreduced lower opening44. In this regard, the opening 44 is made as smallas feasible to achieve maximum support by the material of the bearingmember- 30 for the'underportion of ball head 26, i.e., the portion ofball head 26 proximate the shaft neck 22a. Such support is required whenthe vehicle suspension of (was 451 is preferably the type shown is undertension, as for example, during The assembly is then inserted into thesnugly confining cup 32, whereupon plate 34 is secured in place.

Frequently in automobile wheel suspensions of the type disclosed, theextent of relative pivotal movement of the couplings 16 and 18 is atbest insufficient, so that means are employed to increase the range ofthis movement. It has been common to reduce the diameter of the couplingshaft adjacent the ball head to increase the freedom of pivotal movementof the-shaft with respect to the retainer for the ball head. -Inaccordance with the above-described method of fabricating the ball headcoupling, the initial rod 22, FIGURE 2, is selected having the desiredsmall diameter of the neck 220. During forging of the ball head 26 asdescribed above, the rod 22 is also forged to form the conical bulge 41at the region below neck 22a where the increased thickness is required.Thus the relczluced neck 22a is achieved without undercutting the ballead 26. i

J Although the present invention has been described as being carried outby cold die forging operations, it will n iijlQZ- Pfefiably-theharness-251s formed by a combinaaeti lsstsagi-ii emps, th

the' spheiical I claim:

1. In the process of fabriczi'tifi ballh of a shaft, the steps ofproviding a shaft of material, mushrooming one end of said shaft toeffect an integral spherical dome having a flared annular base extendingradially from said shaft to an annular edge, and deforming said basearound said shaft and lengthwise thereof in the direction from said oneend toward the opposite end of said shaft to effect a sphericalcontinuation of said dome with the material adjacent said annular edgein close proximity to said shaft.

2. In the process of fabricating a ballhead on the end of a shaft, thesteps of providing a shaft of malleable material, mushrooming one end ofsaid shaft to effect an integral spherical dome having a flared annularbase extending radially from said shaft to an annular edge, anddeforming said base around said shaft and lengthwise thereof in thedirection from said one end toward the" opposite end of said shaft toeffect a spherical continuation between said shaft and the portions ofthe spherically deformed base from its juncture with said shaft to saidannular edge.

3. In the process of fabricating a ball head on the end of a shaft, thesteps of providing a shaft of malleable material, mushrooming one end ofsaid shaft to effect an integral rounded dome having a flared annularbase extending radially from said shaft to an annular edge, forging themushroomed end of said shaft to extend said base around said shaft inspaced relationship therewith and axially therealong in the directionfrom said one end toward the opposite end of said shaft to effect arounded end for said shaft defined by an outer cylindrical surface ofsaid base extending coaxially with said shaft and merging tangentiallywith the rounded surface of said dome. and then to recurve said baseradially toward said shaft to effect a ball end for said shaft definedby a continuous ball-like surface of said dome and base terminating atsaid annular edge around and adjacent said shaft at the side of saidball end opposite said dome.

4. In the process of fabricating a ball head on the end of a shaft, thesteps of providing a shaft of malleable material, mushrooming one end ofsaid shaft to effect an integral rounded dome having a flared annularbase extending radially from said shaft to an annular edge, forging themushroomed end of said shaft to extend said base coaxially along saidshaft from said dome in spaced remalleable lationship around said shaftand then to recurve said base toward said shaft to effect a ball end forsaid shaft defined by a continuous ball-like surface of said dome andbase terminating at said annular edge around and adjacent said shaft atthe side of said ball end opposite said dome.

5. 1m the process of fabricating a ball head on the end of a shaft, thesteps of providing a shaft of malleable material, mushrooming one end ofsaid shaft to effect an integral rounded dome having a flared annularbase extending radially from said shaft to an annular edge, forging themushroomed end of said shaft to extend said base coaxially along saidshaft from said dome in spaced relationship around said shaft and thento recurve said base toward said shaft to effect a ball end for saidshaft defined by a continuous ball-like surface of said dome and baseterminating at said annular edge around and adjacent said shaft at theside of Said ball end opposite said dome, and also forging said shaft toenlarge the diameter thereof at a region adjacent and spaced axiallyfrom said ball end.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN THE PROCESS OF FABRICATING A BALL HEAD ON THE END OF A SHAFT, THE STEPS OF PROVIDING A SHAFT OF MALLEABLE MATERIAL, MUSHROOMING ONE END OF SAID SHAFT TO EFFECT AN INTEGRAL SPHERICAL DOME HAVING A FLARED ANNULAR BASE EXTENDING RADIALLY FROM SAID SHAFT TO AN ANNULAR EDGE, AND DEFORMING SAID BASE AROUND SAID SHAFT AND LENGTHWISE THEREOF IN THE DIRECTION FROM SAID ONE END TOWARD THE OPPOSITE END OF SAID SHAFT TO EFFECT A SPHERICAL CONTINUATION OF SAID DOME WITH THE MATERIAL ADJACENT SAID ANNULAR EDGE IN CLOSE PROXIMITY TO SAID SHAFT. 